The present invention relates to a blood pressure measuring apparatus which non-invasively measures the blood pressure.
As a blood pressure measuring apparatus which non-invasively measures the blood pressure, a blood pressure measuring apparatus is usually employed in which the blood pressure is measured by first inflating the cuff pressure to a pressure that is sufficiently higher than the systolic blood pressure (for example, a cuff pressure that is higher than the systolic blood pressure by 40 mmHg), and, while then deflating the cuff pressure, detecting pressure oscillation that is produced in the cuff pressure by pulsation, as an oscillation signal. There is a blood pressure measuring apparatus in which the blood pressure is measured while inflating the cuff pressure, in order to shorten the time required for measurement as compared with the blood pressure measurement that measures the blood pressure while deflating the cuff pressure (for example, see JP-A-8-322811).
In the process of inflating the cuff pressure, however, air is ejected from an air pump to a cuff, and hence periodic oscillation due to driving of the air pump is superimposed as noise on pressure oscillation in the cuff caused by pulsation. In the case where the cycle of the oscillation due to driving of the air pump is similar to that of the pulsation component which is a principal component of a pulse wave, therefore, it is difficult to measure a correct blood pressure from the oscillation signal.
In the related-art blood pressure measurement performed during the process of deflating the cuff pressure, when the systolic blood pressure is to be measured, moreover, the cuff must be pressurized by a pressure which is sufficiently higher than the systolic blood pressure. The pressurization may sometimes cause a burden on the subject (the patient or the like). Therefore, it is requested to develop accurate blood pressure measurement in which the burden on the patient is low, and which can be rapidly performed.